Android: Decouple animate from vsync

content/browser/renderer_host/compositor_impl_android.h

Index: content/browser/renderer_host/compositor_impl_android.h
diff --git a/content/browser/renderer_host/compositor_impl_android.h b/content/browser/renderer_host/compositor_impl_android.h
index 91de0aee2a9b259b5d3acbad4988c8b3a202b93c..0dc827005e00b5af60f6968b519d9afe647cfb04 100644
--- a/content/browser/renderer_host/compositor_impl_android.h
+++ b/content/browser/renderer_host/compositor_impl_android.h
@@ -6,10 +6,10 @@
 #define CONTENT_BROWSER_RENDERER_HOST_COMPOSITOR_IMPL_ANDROID_H_
 
 #include "base/basictypes.h"
+#include "base/cancelable_callback.h"
 #include "base/compiler_specific.h"
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
 #include "cc/resources/ui_resource_client.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
@@ -104,13 +104,36 @@ class CONTENT_EXPORT CompositorImpl
       scoped_ptr<cc::CopyOutputRequest> request) OVERRIDE;
   virtual void OnVSync(base::TimeTicks frame_time,
                        base::TimeDelta vsync_period) OVERRIDE;
+  virtual void SetNeedsAnimate() OVERRIDE;
 
-  void PostComposite(base::TimeDelta delay);
   enum CompositingTrigger {
+    DO_NOT_COMPOSITE,
     COMPOSITE_IMMEDIATELY,
-    COMPOSITE_ON_VSYNC
+    COMPOSITE_EVENTUALLY,
   };
+  void PostComposite(CompositingTrigger trigger);
   void Composite(CompositingTrigger trigger);
+
+  bool WillCompositeThisFrame() const {
+    return current_composite_task_ &&
+           !current_composite_task_->callback().is_null();
+  }
+  bool DidCompositeThisFrame() const {
+    return current_composite_task_ &&
+           current_composite_task_->callback().is_null();
+  }
+  bool WillComposite() const {
+    return WillCompositeThisFrame() ||
+           composite_on_vsync_trigger_ != DO_NOT_COMPOSITE;
+  }
+  void CancelComposite() {
+    DCHECK(WillComposite());
+    if (WillCompositeThisFrame())
+      current_composite_task_->Cancel();
+    current_composite_task_.reset();
+    composite_on_vsync_trigger_ = DO_NOT_COMPOSITE;
+    will_composite_immediately_ = false;
+  }
   cc::UIResourceId GenerateUIResourceFromUIResourceBitmap(
       const cc::UIResourceBitmap& bitmap,
       bool is_transient);
@@ -144,20 +167,24 @@ class CONTENT_EXPORT CompositorImpl
   // explicit request.
   bool needs_composite_;
 
-  // When SetNeedsComposite() is getting called, we will try to schedule
-  // regularly during vsync.
-  bool should_composite_on_vsync_;
+  // Whether we need to update animations on the next composite.
+  bool needs_animate_;
+
+  // Whether we posted a task and are about to composite.
+  bool will_composite_immediately_;
 
-  // Whether we composited already in the current vsync interval.
-  bool did_composite_this_frame_;
+  // How we should schedule Composite during the next vsync.
+  CompositingTrigger composite_on_vsync_trigger_;
+
+  // The Composite operation scheduled for the current vsync interval.
+  scoped_ptr<base::CancelableClosure> current_composite_task_;
 
   // The number of SwapBuffer calls that have not returned and ACK'd from
   // the GPU thread.
   unsigned int pending_swapbuffers_;
 
   base::TimeDelta vsync_period_;
-
-  base::WeakPtrFactory<CompositorImpl> weak_factory_;
+  base::TimeTicks last_vsync_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorImpl);
 };